limp mode after new head gasket/studs

[Fox_91]

just put a new head gasket and studs on the 12' 3500 4x4 cummins, now it seems to be in a fuel limp, flashing a ECM code, is there a plug im missing? havnt had a chance to check it back out, will tomorrow morning tho. truck has a s466, h&s, fully deleted, and a AD fuel system. truck will get up to speed but takes about 2 miles to get to 55.ran perfect other than the external coolant leak before head gasket/stud job.

 

[Gibson]

What is the rail pressure?

 

[Fox_91]

un hooked batteries for a few minutes and while they were un hooked found a plug back back of the head that didnt have the safety hook clipped fully, and started it up, runs/drives great now.